JP5018150B2 - Fuel cell, electronic device, fuel supply plate, and fuel supply method - Google Patents

Description

  The present invention relates to a fuel cell that generates electric power by reaction of methanol and oxygen, an electronic device incorporating such a fuel cell, a fuel supply plate used in such a fuel cell, and a fuel supply method.

  When a battery is used as a power source, in order to obtain a voltage necessary for a load, a high voltage is often obtained by connecting a necessary number of unit cells in series. In particular, in a fuel cell, since the power generation voltage per unit cell is low, it is customary to configure a battery system by connecting a plurality of unit cells (power generation units) in series.

In such a battery system, a plurality of unit cells are usually stacked vertically with a current collector plate in between. Moreover, the flow path for supplying a fuel or air to a battery cell is provided in the both surfaces or single side | surface of the current collecting plate (for example, refer patent document 1).
JP 2004-140153 A

  However, when a plurality of unit cells are arranged in the in-plane direction, the distance between the outlet of the fuel supply pump and each unit cell is different, resulting in variations in the amount of fuel supplied to each unit cell. . For this reason, the electromotive force of each unit cell varies, and the output of the entire battery system is greatly reduced. Furthermore, depending on the configuration of the battery system, there are many cases where the position of the outlet of the fuel supply pump cannot be freely changed, and it has been extremely difficult to supply fuel to each unit cell in an equal amount.

  The present invention has been made in view of such problems, and an object thereof is to provide a fuel cell, an electronic device, a fuel supply plate, and a fuel supply method that can uniformly supply fuel to a plurality of power generation units. is there.

  The fuel cell according to the present invention includes a battery main body including a plurality of power generation units, a fuel tank that stores liquid fuel, an inlet through which liquid fuel is supplied from the fuel tank, and a plurality of outlets that respectively correspond to the plurality of power generation units. The plurality of flow paths include at least one fuel supply plate that includes a curve and is equidistant. Here, “all are equidistant” means that the distance between the inlet and the outlet is the same in all of the plurality of flow paths.

  The electronic device of the present invention incorporates the fuel cell of the present invention.

  The fuel supply plate of the present invention is for supplying liquid fuel stored in a fuel tank to a plurality of power generation units, and includes an inlet to which liquid fuel is supplied from the fuel tank and the plurality of power generation units. A plurality of corresponding outlets and a plurality of flow paths formed between the inlets and the plurality of outlets and including at least one curved line and all equidistant are provided.

  The fuel supply method of the present invention is a method for supplying liquid fuel stored in a fuel tank to a plurality of power generation units, supplying liquid fuel to an inlet of a fuel supply plate, and including at least one curve. At the same time, they are made to reach a plurality of outlets through a plurality of channels at equal distances and supplied to the power generation units corresponding to each of the plurality of outlets.

  In the fuel cell, the electronic device, and the fuel supply plate of the present invention, the liquid fuel accommodated in the fuel tank is supplied to the inlet of the fuel supply plate, and then reaches a plurality of outlets through a plurality of flow paths. It is supplied to the power generation unit corresponding to the outlet. The plurality of flow paths include at least one curve, and the plurality of flow paths are all equidistant by adjusting the shape of the curve and the bending (curvature radius). Therefore, regardless of the length of the linear distance between the inlet and the plurality of outlets, substantially the same amount of liquid fuel reaches the plurality of outlets at substantially the same timing and is supplied to each power generation unit.

  According to the fuel cell, the electronic device or the fuel supply plate of the present invention, a plurality of flow paths connect between an inlet through which liquid fuel is supplied from the fuel tank and a plurality of outlets respectively corresponding to the plurality of power generation units, Since the plurality of flow paths include at least one curve and are all equidistant, liquid fuel can be uniformly supplied to the plurality of power generation units. Therefore, it is possible to reduce variations in the electromotive force of the plurality of power generation units due to variations in the fuel supply amount, and improve the output of the entire fuel cell.

  According to the fuel supply method of the present invention, the liquid fuel accommodated in the fuel tank is supplied to the inlet of the fuel supply plate, and from there, at least one includes a curve and passes through a plurality of channels that are all equidistant. Since the plurality of outlets are reached and supplied to the corresponding power generation units, the liquid fuel can be uniformly supplied to the plurality of power generation units. Therefore, it is possible to reduce variations in electromotive force of a plurality of power generation units due to variations in the amount of fuel supply, and improve the output of the entire fuel cell.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a cross-sectional configuration of a fuel cell (fuel cell 1) according to an embodiment of the present invention. FIG. 2 shows a configuration of the fuel cell 1 shown in FIG. It is a representation. The fuel supply method of the present invention is embodied by the fuel cell device according to the present embodiment, and will be described below.

  The fuel cell 1 is provided with a fuel tank 20 that contains a liquid fuel (for example, methanol water) 21, and a battery body 5 is provided above the fuel tank 20. The battery body 5 includes a plurality (for example, six) of battery cells 5A to 5F arranged along the horizontal direction. The fuel tank 20 includes, for example, a container (for example, a plastic bag) whose volume is changed without bubbles or the like even when the liquid fuel 21 increases or decreases, and a rectangular parallelepiped case (structure) that covers the container. Consists of.

  Each of the battery cells 5A to 5F is a direct methanol type power generation unit that generates power by a reaction between methanol and oxygen, and a fuel electrode (anode electrode, negative electrode) 51 and an oxygen electrode (cathode electrode, (Positive electrode) 53 is disposed to face each other. An air supply pump (not shown) is connected to the oxygen electrode 53, and the fuel electrode 51 is formed on the fuel tank 20 side of the battery cells 5A to 5F. The electrolyte membrane 52 is made of, for example, a proton conductor.

  In the fuel tank 20, a fuel supply pump 22 for sucking the liquid fuel in the fuel tank 20 and discharging it from the nozzle 23 is provided. A fuel supply plate 3 for supplying the liquid fuel 21 discharged from the nozzle 23 to the battery cells 5A to 5F between the fuel tank 20 and the battery cells 5A to 5F, specifically on the upper surface of the fuel tank 20. Is provided. A fuel leakage prevention unit 41 is provided between the battery cells 5A to 5F and between these and the fuel supply plate 3 so that the liquid fuel 21 can be prevented from leaking.

  FIG. 3 shows an example of the configuration of the fuel supply plate 3 viewed from the battery body 5 side. The fuel supply plate 3 has an inlet IL to which the liquid fuel 21 is supplied from the fuel tank 20 and six outlets OL corresponding to the battery cells 5A to 5F, respectively, and six flow paths 3A between them. ~ 3F is formed. These flow paths 3A to 3F branch the liquid fuel 21 from the inlet IL to the six outlets OL and move the liquid fuel 21. The dimensions such as the width and depth of the liquid fuel 21 are the transport method (for example, pump or Appropriately set according to the use of capillarity. In addition, each exit OL should just be open | released toward battery cell 5A-5F, and does not necessarily need to be connected to battery cell 5A-5F.

  The flow paths 3A to 3F include curves CA to CF, respectively, and are all equidistant. Thereby, in this fuel cell 1, the liquid fuel 21 can be uniformly supplied to the battery cells 5A to 5F. In addition, although the flow paths 3A-3F may be comprised only with the curve, you may include the straight line in the part immediately after the branch in the vicinity of entrance IL as needed, for example.

  The curves CA to CF are used to make the distance between the inlet IL and the outlet OL equal in all of the flow paths 3A to 3F by adjusting the shape and bending (radius of curvature). Is. The inlet IL is defined by the position of the outlet of the nozzle 23 of the fuel supply pump 22, and may be displaced from the center of the fuel supply plate 3 as shown in FIG. 3, for example. The outlet OL is defined by the shape, size, arrangement, and interval of the battery cells 5A to 5F. Usually, battery cell 5A-5F is a rectangle, and the outlet OL is provided in the center of each battery cell 5A-5C. It is difficult to freely change the positions of the inlet IL and the outlet OL.

  The flow paths 3A to 3F preferably include arcs as the curves CA to CF. This is because the length of the arc can be easily calculated, and drafting and processing can be facilitated. FIG. 3 illustrates a case where the flow paths 3A to 3F include arcs and straight lines. However, the shapes of the curves CA to CF may be other curves such as an ellipse or a Bezier curve in addition to the arc, and are not particularly limited.

  It is desirable to make the curvature radii of the curves CA to CF as large as possible. This is because the flow is not complicated and structure determination by complicated fluid simulation can be avoided.

  The flow paths 3A to 3F are all equidistant regardless of the position of the inlet IL. FIG. 4 illustrates an example of the flow paths 3 </ b> A to 3 </ b> F when the inlet IL coincides with the center of the fuel supply plate 3. The flow paths 3A to 3F shown in FIG. 4 are different from those shown in FIG. 3 in curves (curvature radii) of curves CA to CF, but are all equidistant.

  As shown in FIG. 3 or FIG. 4, such flow paths 3A to 3F have an n-gonal shape N (n is the number of flow paths 3A to 3F) from the entrance IL to the center of the present embodiment. In the form, it is preferably 6). When the flow paths 3A to 3F are branched from the middle without being directly branched from the inlet IL, the flow paths 3A to 3F can be designed geometrically and simply to equally divide the liquid fuel 21 due to the influence of the flow inertia. It will be difficult.

  Further, the n-gon N is more preferably a regular n-gon (a regular hexagon in the present embodiment). This is because the liquid fuel 21 can be equally branched into the flow paths 3A to 3F. The “regular n-gon” here has not only a geometrically perfect regular n-gon but also a symmetry that can be said to be almost a regular n-gon in consideration of the processing accuracy of the flow paths 3A to 3F. It also includes n-gons. That is, in the flow paths 3A to 3F, the angle θ formed by the straight portion immediately after branching between the two adjacent flow paths is larger than 360 ÷ (n + 1) and smaller than 360 ÷ (n−1). It only has to be arranged.

  In addition, the flow paths 3A to 3F preferably have no corners. This is because the angle may significantly disturb the flow regardless of the acute obtuse angle.

  FIG. 5 shows an example of a specific configuration of such a fuel supply plate 3. For example, the fuel supply plate 3 includes, in order from the fuel tank 20 side, a tank side supply plate 31 in which an inlet IL is formed, a channel plate 32 in which channels 3A to 3F are formed, and six outlets OL. In addition, the cell side supply plate 33 can be stacked.

  The tank side supply plate 31 is made of, for example, a metal plate such as stainless steel having a thickness of about 0.3 mm, and also has a function of ensuring the strength of the fuel supply plate 3. The diameter of the inlet IL is, for example, about 1 mm.

  The flow path plate 32 has a thickness of, for example, about 50 μm, is constituted by a maleic acid-modified polypropylene double-sided adhesive sheet, and is provided with cutouts in accordance with the outer shapes of the flow paths 3A to 3F. Note that a cutout wider than the inlet IL may be provided as a fuel reservoir near the inlet IL of the flow paths 3A to 3F.

  For example, the cell side supply plate 33 has a thickness of about 0.1 mm and is made of a metal plate such as stainless steel.

  The cell side supply plate 33 is provided with six through holes as outlets OL. Thus, by providing the cell side supply plate 33 in addition to the flow path plate 32, the diameter of the outlet OL is made smaller than the width of the flow paths 3A to 3F, and the outlet OL has a function of adjusting the pressure of the liquid fuel 21. Can be made. That is, by making the outlet OL narrower than the flow paths 3A to 3F, pressure loss can be caused (decompression function), and the liquid fuel 21 can always be discharged from the outlet OL at a constant pressure (pressure regulation function). In addition, by doing this, even when the fuel cell 1 is tilted, the liquid fuel 21 can be discharged from the outlet OL without being affected by gravity. For this purpose, it is desirable that the diameter of the outlet OL is as small as possible, for example, 1 mm or less, specifically about 0.3 mm. Note that, instead of reducing the outlet OL, the width of the flow paths 3A to 3B can be reduced in the middle, the thickness of the double-sided adhesive sheet can be reduced, or a pressure valve (not shown) can be provided at the outlet OL. Can be obtained.

  FIG. 6 shows a fluid simulation result in the case where the flow paths 3A to 3F are formed as shown in FIG. 3, and only half of the structure is modeled considering the mirror plane. In FIG. 6, the fuel discharge rates from the channels A to C are 0.844 mL / s, 0.851 mL / s, and 0.847 mL / s, respectively, and the deviations from the three average values are −0.42 respectively. %, + 0.45%, and -0.03%. In FIG. 6, the color (darkness) of the wall surfaces of the channels A to C indicates the pressure applied to the wall surface, and the pressure decreases as the color changes from warm (light) to cold (dark). The vicinity of the inlet becomes high under the influence of the pumping pressure, and the vicinity of the outlet becomes low because it is almost equal to the atmospheric pressure. The thin lines in the channels A to C indicate the direction and amount of the flow, and the flow rate is high where the fine line density is high and the flow rate is low where the density is low.

In the model, since the flow paths A to C are filled with methanol, the density and viscosity use methanol values. The density value actually used was 0.791 g / cm ³ , and the viscosity was 0.54 mPa.s. s. Further, it is assumed that the whole model is subjected to body force (gravity), and the value is 7.76 kN / m ³ (value obtained by multiplying the acceleration of gravity by the density of methanol). As boundary conditions, the pressure at the methanol inlet is 115 kPa (a value obtained by adding the pump head to the atmospheric pressure), and the outlet is 100 kPa (atmospheric pressure). In addition, all the boundaries where methanol does not enter and exit are defined as slip surfaces. For the calculation, an incompressible Navier-Stokes equation is used, and a finite element method calculation is performed using a stationary linear solver. The calculation conditions are as follows: the pump pressure is 15 kPa, the inlet IL is 2 mm in diameter, the outlet OL is 0.3 mm in diameter, the back pressure is uniform, the temperature is 30 ° C., and the installation direction is supine.

  FIG. 7 shows the result of the fluid simulation performed under the same conditions as in FIG. 6 when the flow path is a straight line. Similar to FIG. 6, only half of the structure considering the mirror surface is modeled. ing. In FIG. 7, the fuel discharge rates from the channels A to C are 0.844 mL / s, 2.402 mL / s, and 1.678 mL / s, respectively, and the deviations from the three average values are −48.6, respectively. %, + 46.4%, and + 2.25%.

  Comparing the results of FIG. 6 and FIG. 7, FIG. 6 shows that the variation in the fuel discharge amount from each of the flow paths A to C is greatly suppressed compared to FIG. It can be seen that the equidistant flow path pattern including this greatly contributes to uniform fuel ejection.

  The fuel cell 1 can be manufactured, for example, as follows.

  First, the tank-side supply plate 31 and the cell-side supply plate 33 made of the above-described thickness and material are prepared, and the inlet IL is formed in the tank-side supply plate 31 by, for example, processing using photoetching, and the cell-side supply plate Six outlets OL are formed in 33.

  Next, the flow path plate 32 made of, for example, the above-described thickness and material is provided with a cutout that matches the shape of the flow paths 3A to 3F, for example, by punching with a press, and the tank side supply plate with the flow path plate 32 in between. The fuel supply plate 3 is formed by pasting 31 and the cell side supply plate 33 together.

  Subsequently, the fuel supply plate 3 is installed on the fuel tank 20 to which the fuel supply pump 22 and the nozzle 23 are attached. After that, the battery body 5 and the fuel leakage prevention part 41 made of the above-described material are provided on the fuel supply plate 3. Thus, the fuel cell device 1 shown in FIG. 1 is manufactured.

  By this manufacturing method, the tank side supply plate 31 is a stainless steel plate having a thickness of 0.3 mm, the flow path plate 32 is a double-sided adhesive sheet made of maleic acid-modified polypropylene having a thickness of 50 μm, and the cell side supply plate 33 is a thickness of 0.1 mm. A fuel supply plate 3 having a stainless steel plate and an outlet OL diameter of 0.3 mm was actually manufactured, and the obtained fuel supply plate 3 was affixed to the fuel supply pump 22 to perform an operation check test. When the amount of fuel ejected from the 33 outlets OL was visually confirmed, almost the same amount of fuel was ejected from all the outlets OL. Further, when an operation check test was performed in the same manner by changing the installation direction of the fuel supply pump 22, the amount of fuel ejected did not change even when the fuel supply pump 22 was laid on its back or stood.

  In this fuel cell device 1, the liquid fuel 21 accommodated in the fuel tank 20 is supplied to the inlet IL of the fuel supply plate 3 by the fuel supply pump 22 and the nozzle 23, and from there, the flow path 3 </ b> A by the pressure of the fuel supply pump 22 It reaches the outlet OL via ~ 3F and vaporizes. The vaporized fuel passes through the separation sheet 42 and reaches each of the battery cells 5 </ b> A to 5 </ b> C and is supplied to each of the fuel electrodes 51. On the other hand, air (oxygen) is supplied to the oxygen electrodes 53 of the battery cells 5A to 5C by an air supply pump (not shown). Then, in each fuel electrode 51, hydrogen ions and electrons are generated by the reaction. Further, the hydrogen ions move to the oxygen electrode 53 through the electrolyte membrane 52, react with electrons and oxygen to generate water, and carbon dioxide is by-produced. In this way, the power generation operation is performed in the fuel cell 1.

  Here, since the flow paths 3A to 3F include the curves CA to CF, respectively, and are all equidistant, substantially equal amounts of the liquid fuel 21 regardless of the length of the linear distance between the inlet IL and the six outlets OL. Arrives at the exit OL at approximately the same timing and vaporizes. Therefore, the vaporized fuel is evenly supplied to the battery cells 5A to 5F, variation in the electromotive force of the battery cells 5A to 5F is reduced, and the overall output of the fuel cell 1 is improved.

  As described above, in the present embodiment, the inlet IL and the six outlets OL are connected to each other by the equidistant flow paths 3A to 3F including the curves CA to CF, respectively, and these flow paths 3A to 3F are connected. Therefore, the liquid fuel 21 can be uniformly supplied to the battery cells 5A to 5F. Therefore, the variation in electromotive force of the battery cells 5A to 5F due to the variation in the fuel supply amount can be reduced, and the output of the entire fuel cell can be improved.

  In particular, since the flow paths 3A to 3F include arcs as the curves CA to CF, drafting and processing can be facilitated.

  Further, since the flow paths 3A to 3F are formed in a direction from the inlet IL toward the apex of the n-gon N (n is the number of the flow paths 3A to 3F) centering on the inlet IL, the liquid fuel 21 is The flow paths 3A to 3F can be evenly branched.

  Further, since the n-gon N is a regular n-gon, the liquid fuel 21 can be more evenly branched into the flow paths 3A to 3F.

  In addition, since the flow paths 3A to 3F have no corners, it is possible to eliminate the possibility that the flow of the liquid fuel 21 is disturbed.

  While the present invention has been described with reference to the embodiment, the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above-described embodiment, the case where the flow paths 3A to 3F include the curves CA to CF has been described. However, as long as the flow paths 3A to 3F are all equidistant, all the flow paths 3A to 3F have curves. It is not necessary to be included, and it is sufficient that at least one of the flow paths 3A to 3F includes a curve.

  In the above embodiment, the configuration of the fuel cell 1 and the fuel supply plate 3 has been specifically described. However, the fuel cell 1 or the fuel supply plate 3 may be configured by other structures or other materials. Good. For example, in the fuel supply plate 3, the tank side supply plate 31 may be omitted and only the flow path plate 32 and the cell side supply plate 33 may be provided. In that case, the inlet IL can be provided in the flow path plate 32. Further, the flow path plate 32 may be formed by providing a heat fusion layer such as polypropylene on both surfaces of a metal plate made of aluminum (Al) or an alloy containing aluminum (Al) instead of the double-sided adhesive sheet. For example, in the fuel cell 1, the case where the six battery cells 3 </ b> A to 3 </ b> F are arranged in 3 rows × 2 columns has been described. However, the number and arrangement of the battery cells are not particularly limited, and eight battery cells are arranged in four. It can be changed as appropriate, for example, by arranging in rows and two columns.

  Furthermore, for example, the material and thickness of each component described in the above embodiment or the power generation conditions of the fuel cell are not limited, and may be other materials and thicknesses, or other power generation conditions. Good.

  In addition, for example, in the above-described embodiment, the case where the liquid fuel 21 is vaporized and the vaporized fuel is supplied to the battery cells 5A to 5F has been described. However, in the present invention, the fuel is brought into contact with the fuel electrode in a liquid state. This can also be applied to the case of supplying the product.

  Furthermore, in the above embodiment, the fuel tank 20 is sealed, and the liquid fuel 21 is supplied as necessary. However, the fuel electrode 51 is supplied with fuel from a fuel supply unit (not shown). It may be. Further, for example, the liquid fuel 21 may be other liquid fuel such as ethanol or dimethyl ether in addition to methanol.

  In addition, the present invention is not limited to fuel cells that use liquid fuel, but can also be applied to fuel cells that use substances other than liquid fuel, such as hydrogen, as fuel.

  The fuel cell of the present invention is, for example, a portable type such as a cellular phone, an electrophotographic machine, an electronic notebook, a notebook personal computer, a camcorder, a portable game machine, a portable video player, a headphone stereo, or a PDA (Personal Digital Assistants). It can be suitably used for electronic devices.

It is sectional drawing showing the structure of the fuel cell which concerns on one embodiment of this invention. It is a top view showing the structure seen from the battery main body side of the fuel cell shown in FIG. It is a top view showing the structure seen from the battery main body side of the fuel supply board shown in FIG. FIG. 4 is a plan view illustrating another configuration of the fuel supply plate illustrated in FIG. 3. It is a disassembled perspective view showing the structure of the fuel supply plate shown in FIG. It is a figure showing the fluid simulation result in the fuel supply board which has the flow-path structure shown in FIG. It is a figure showing the fluid simulation result in another example of channel composition.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell, 20 ... Fuel tank, 21 ... Liquid fuel, 22 ... Fuel supply pump, 23 ... Nozzle, 3 ... Fuel supply plate, 3A-3F ... Channel, 31 ... Tank side supply plate, 32 ... Channel plate , 33 ... cell side supply plate, 41 ... fuel leakage prevention part, 5 ... battery main body, 5A to 5F ... battery cell, 51 ... fuel electrode (anode electrode, negative electrode), 52 ... electrolyte membrane, 53 ... oxygen electrode (cathode) Pole, cathode), CA to CF ... curve, IL ... inlet, OL ... outlet

Claims (12)

A battery body including a plurality of power generation units;
A fuel tank containing liquid fuel;
A plurality of flow paths are provided between an inlet through which liquid fuel is supplied from the fuel tank and a plurality of outlets respectively corresponding to the plurality of power generation units, and the plurality of flow paths include at least one curve. And a fuel supply plate, all of which are equidistant. The fuel cell according to claim 1, wherein the plurality of flow paths include at least one arc. The plurality of flow paths are formed in a direction from the inlet toward an apex of an n-gon (n is the number of the plurality of flow paths) centered on the inlet. Fuel cell. The fuel cell according to claim 3, wherein the n-gon is a regular n-gon. The fuel cell according to claim 1, wherein the plurality of flow paths have no corners. An electronic device with a built-in fuel cell,
The fuel cell
A battery body including a plurality of power generation units;
A fuel tank containing liquid fuel;
A plurality of flow paths between an inlet to which liquid fuel is supplied from the fuel tank and a plurality of outlets respectively corresponding to the plurality of power generation units, the plurality of flow paths including at least one curve; An electronic device comprising a fuel supply plate that is all equidistant. A fuel supply plate for supplying liquid fuel stored in a fuel tank to a plurality of power generation units,
An inlet through which liquid fuel is supplied from the fuel tank;
A plurality of outlets respectively corresponding to the plurality of power generation units;
A fuel supply plate, comprising: a plurality of flow paths formed between the inlet and the plurality of outlets, including at least one curved line and all equidistant. The fuel supply plate according to claim 7, wherein the plurality of flow paths include at least one arc. The plurality of flow paths are formed in a direction from the inlet toward an apex of an n-gon (n is the number of the plurality of flow paths) centered on the inlet. Fuel supply plate. The fuel supply plate according to claim 9, wherein the n-gon is a regular n-gon. The fuel supply plate according to claim 7, wherein the plurality of flow paths have no corners. A method for supplying liquid fuel stored in a fuel tank to a plurality of power generation units,
The liquid fuel is supplied to an inlet of a fuel supply plate, and at least one of them includes a curve and reaches a plurality of outlets through a plurality of channels that are all equidistant, and the power generation corresponding to each of the plurality of outlets A fuel supply method comprising: supplying to a fuel cell.

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